In the manufacture of semiconductor circuits on wafers, the wafers are periodically coated with photoresist to fabricate the various layers of circuitry, electrical devices and vias and interconnects. After photoresist is developed and used, etching and ashing are performed resulting in residues that must be removed before further processing. Strippers have been utilized to remove unwanted photoresist and the residues of etching and ashing. The photoresist, etch residue or ash residue is difficult to selectively remove without damaging the desired circuit structures. The stripper must be compatible with dielectric and metal conductive materials. The corrosion rate of either of these differing types of materials must be within acceptable levels.
Commercially available strippers for the application of thick dry film (usually range from 70 to 120 micrometer (micron (μm))) removal comprise a mixture of dimethylsulfoxide (DMSO) and tetramethylammonium hydroxide (TMAH). These strippers usually operate at elevated temp (>90° C.) and suffer from short bath-life issues. Strippers in this field are described in U.S. 2005/0263743, U.S. 2006/0094613 and U.S. 2006/0115970.